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不同前茬作物和施肥水平下麦田土壤不同形态无机磷含量及其对冬小麦磷累积量的贡献

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河南师范大学学报（自然科学版） 2025年第1期53卷 23-31,F0002页

作者：邵云王岚王鹏飞侯盟安佳慧赵宇浩河南师范大学生命科学学院河南新乡453007

为研究不同前茬作物下土壤无机磷形态的差异及对后茬作物冬小麦磷累积的影响,开展了二因素田间试验,测定了3种前茬作物(玉米、大豆、花生)和2个磷肥施肥水平(P_(2)O_(5)150 kg/hm^(2),常规施肥(+F);P_(2)O_(5)0 kg/hm^(2),限肥(-F))处... 详细信息

为研究不同前茬作物下土壤无机磷形态的差异及对后茬作物冬小麦磷累积的影响,开展了二因素田间试验,测定了3种前茬作物(玉米、大豆、花生)和2个磷肥施肥水平(P_(2)O_(5)150 kg/hm^(2),常规施肥(+F);P_(2)O_(5)0 kg/hm^(2),限肥(-F))处理下播种前和收获后耕层(0~15 cm)土壤全磷、速效磷以及不同形态无机磷的质量分数,同时测定冬小麦植株磷累积量,运用通径分析法,分析了土壤中不同形态无机磷对冬小麦植株磷积累量的贡献.结果表明:与常规施肥相比,限肥显著降低土壤全磷、速效磷和不同形态无机磷的含量.在常规施肥水平下,玉米前茬处理的土壤速效磷质量分数最高且显著高于其他前茬处理,为18.61 mg/kg,总无机磷、Fe-P和Ca_(10)-P的质量分数也最高,分别为592.55 mg/kg、41.97 mg/kg和338.77 mg/kg;大豆前茬处理的土壤全磷质量分数最高且显著高于其他前茬处理,为972.80 mg/kg,Al-P和O-P的含量也在大豆前茬处理的质量分数最高,分别为43.44 mg/kg和64.37 mg/kg;花生前茬处理的土壤Ca_(2)-P和Ca_(8)-P的质量分数最高,分别为27.53 mg/kg和94.14 mg/kg,但与玉米前茬和大豆前茬的处理结果差异不显著.在限肥水平下,玉米前茬处理土壤的全磷、速效磷和O-P的质量分数最高且显著高于其他前茬处理,分别为770.47 mg/kg、13.50 mg/kg、58.99 mg/kg;大豆前茬处理土壤Ca_(10)-P的质量分数最高且显著高于其他前茬处理,为320.62 mg/kg,总无机磷、Al-P和Fe-P的质量分数与其他前茬处理差异不显著,分别为541.96 mg/kg、34.50 mg/kg和36.42 mg/kg;花生前茬处理土壤Ca_(2)-P和Ca_(8)-P的质量分数最高但与花生前茬处理的差异不显著,分别为23.04 mg/kg和78.78 mg/kg.2个磷肥水平下冬小麦植株磷累积量均在花生前茬处理下最高,分别为33.11 kg/hm^(2)和25.14 kg/hm^(2).在常规施肥水平下,花生前茬处理与玉米、大豆前茬处理的差异不显著,而在限肥水平下显著高于玉米、大豆前茬处理.经通径分析,土壤无机磷不同形态对冬小麦植株磷累积量的直接影响(直接通径系数)由大到小为Ca_(2)-P、Al-P、Fe-P、Ca_(8)-P、O-P、Ca_(10)-P.结合通径系数和相关系数表明,Ca_(2)-P是小麦磷累积的直接来源,其次是Al-P,而Fe-P和Ca_(8)-P是小麦的缓效磷源,O-P和Ca_(10)-P是小麦比较难以利用的磷源.在2种施肥水平下,前茬作物极显著影响全磷、速效磷、和无机磷的含量,进而影响冬小麦的植株磷累积量.

关键词：冬小麦前茬作物无机磷形态磷累积量通径分析

Robust low friction performance of graphene sheets embedded carbon films coated orthodontic stainless steel archwires

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Friction 2022年第1期10卷 142-158页

作者： Zonglin PAN Qinzhao ZHOU pengfei wang Dongfeng DIAO Institute of Nanosurface Science and Engineering(INSE) Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics EngineeringShenzhen UniversityShenzhen 518060China

Reducing the friction force between the commercial archwire and bracket during the orthodontic treatment in general dental practice has attracted worldwide *** investigation on the friction and wear behaviors of the uncoated and carbon film coated stainless steel archwires running against stainless steel brackets was systematically *** carbon films were prepared at substrate bias voltages from+5 to+50 V using an electron cyclotron resonance plasma sputtering *** increasing substrate bias voltage,local microstructures of the carbon films evolved from amorphous carbon to graphene *** static and stable friction coefficients of the archwire-bracket contacts sliding in dry and wet(artificial saliva)conditions decreased with the deposition of carbon films on the *** friction coefficient of 0.12 was achieved in artificial saliva environment for the graphene sheets embedded carbon(GSEC)film coated *** of the friction behavior of the GSEC film coated archwire occurred after immersion of the archwire in artificial saliva solution for different periods before friction ***,moderate friction coefficient of less than 0.30 sustained after 30 days immersion *** low friction mechanism is clarified to be the formation of salivary adsorbed layer and graphene sheets containing tribofilm on the contact *** robust low friction and low wear performances of the GSEC film coated archwires make them good candidates for clinical orthodontic treatment applications.

关键词： friction steel wear

Experimental Study on Seepage Characteristics of a Soil-Rock Mixture in a Fault Zone

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Fluid Dynamics & Materials Processing 2022年第2期18卷 271-283页

作者： pengfei wang Xiangyang Zhang Key Laboratory of Safety and High-Efficiency Coal Mining Ministry of EducationAnhui University of Science and TechnologyHuainan232001China School of Architecture and Civil Engineering Huangshan UniversityHuangshan245041China

A mixture of fault gouge and rubble taken out from a fault zone is used to prepare a S-RM(Soil-Rock Mixture)sample with rock block proportions of 20%,30%,40%,50%,60%and 70%,respectively.A GDS triaxial test system is used accordingly to measure the seepage characteristics of such samples under different loading and unloading confining pressures in order to determine the variation law of the permeability *** test results show that:(1)The permeability coefficient of the S-RM samples decreases as the pressure increases,and the decrease rate of this coefficient in the initial stage of confining pressure loading is obviously higher than in the semi-late period;(2)The permeability coefficient at different confining pressure levels presents a common trend as the rock block proportion is increased,i.e.,it decreases first then it increases(the permeability coefficient of the sample with rock block proportion 40%being the smallest,70%the largest);(3)In the stage of confining pressure unloading,the recovery degree of the permeability coefficient grows with the increase of rock block proportion(the recovery rate of S-RM sample with rock block proportion 70%reaches 50.2%);(4)In the stage of confining pressure loading and unloading,the sensitivity of the permeability coefficient to the rock block proportion displays the inverse“Z”variation rule(when rock block proportion reaches 60%,the sensitivity is highest);(5)In the stage of confining pressure loading,the relationship between the permeability coefficient and confining pressure can be described by an exponential relationship.

关键词： Fault zone rock block proportion soil-rock mixture confining pressure loading and unloading seepage characteristic

Approximate Perturbation Stance Map of the SLIP Runner and Application to Locomotion Control

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Journal of Bionic Engineering 2012年第4期9卷 411-422页

作者： Haitao Yu Mantian Li pengfei wang Hegao Cai State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150080P.R.China

This paper presents a novel method of perturbation to obtain the analytic approximate solution to the Spring-Loaded Inverted Pendulum （SLIP） dynamics in stance phase with considering the effect of gravity. This perturbation solution achieves higher accuracy in predicting the apex state variables than the typical existing analytic approximations. Particularly, our solution is validated for non-symmetric trajectory of hopping in a large angle range. Furthermore, the stance controller of the SLIP runner is developed to regulate the apex state based on the approximate apex return map. To compensate the energy variation between the current and desired apex states, a stiffness adjustment of the leg spring in stance phase is presented. The deadbeat controller of the angle of attack is designed to track the regulated apex height and velocity. The simulation demonstrates that the SLIP runner applying the proposed stance controller reveals higher tracking accuracy and more rapidly converges to the regulated apex state.

关键词： legged locomotion spring-loaded inverted pendulum perturbation apex return map stiffness adjustment

Thermal Performance of Elliptical Fin-and-Tube Heat Exchangers with Vortex Generator under Various Inclination Angles

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Journal of Thermal Science 2021年第1期30卷 257-270页

作者： wang Yucheng ZHAO Wensheng wang pengfei JIANG Jin LUO Xiangyu Key Laboratory of Hydraulic Machinery Transients Ministry of EducationWuhan UniversityWuhan 430072China School of Power and Mechanical Engineering Wuhan UniversityWuhan 430072China

Elliptical fin-and-tube heat exchangers are commonly used in air conditioning,heating,refrigeration industries,and *** study numerically investigates the effect of vortex generators on the performance of elliptical fin-and-tube heat exchanger under different inclination *** this study,air flow that is in the transitional regime is selected as the working *** numbers at the inlet are varied in a range of 1300 to 2100,and the shear stress transport k-ωturbulence model is selected to solve the non-closure of basic turbulence *** ellipticity ratios of the tubes which are used for the analysis are between 0.6 and 1.0,and the inclination angles are varied from 15°to 75°.The effects of different inclination angles of vortex generators on the Colburn factor j,friction factor f,and efficiency index j/f are *** friction and Colburn factors are observed to increase with increasing vortex generator inclination *** is found that the efficiency factors for a 15°vortex generator inclination angle at 0.6,0.7,0.8,and 0.9 ellipticity ratios improve compared to the corresponding cases with no vortex ***,the vortex generator cannot improve the efficiency factor of the circular tube heat *** 3 D CFD method employed by this study has great potential for use in optimally designing the arrangement of the vortex generators to enhance the performance of heat exchangers.

关键词： heat exchanger vortex generator Colburn factor friction factor heat exchanger efficiency

Research and Application of Non-symmetrical Roll Bending Control of Cold Rolling Mill

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 122-127页

作者： wang pengfei ZHANG Dianhua LI Xu LIU Jiawei wang Junsheng State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110004China Anshan Iron and Steel Company Anshan 114001China

The existing research of the flatness control for strip cold rolling mainly focuses on the calculation of the optimum adjustment of individual flatness actuator in accordance with the flatness deviation, which can be used for general flatness control. However, it does not work for some special rolling processes, such as the elimination of ultra single side edge-waves and the prevention of strip break due to tilting roll control overshooting. For the purpose of solving these problems, the influences of non-symmetrical work roll bending and intermediate roll bending on flatness control were analyzed by studying efficiencies of them. Moreover, impacts of two kinds of non-symmetrical roll bending control on the pressure distribution between rolls were studied theoretically. A non-symmetrical work roll bending model was developed by theoretical analysis in accordance with practical conditions. The model was applied to the revamp of a 1250 6-H reversible universal crown mill (UCM) cold mill. Theoretical study and practical applications show that the coordination utilization of the non-symmetrical work roll bending control and tilting roll control was effective in flatness control when there appeared bad strip single side edge waves, especially when the incoming strip was with a wedge shape. In addition, the risk of strip break due to tilting control overshooting could be reduced. Furthermore, the non-symmetrical roll bending control can reduce the extent of uneven distribution of pressure between rolls caused by intermediate roll shifting in flatness control and slow down roll wear. The non-symmetrical roll bending control technology has important theoretical and practical significance to better flatness control.

关键词： non-symmetrical roll bending flatness control cold rolling actuator efficiency roll wear strip break

Deviation matrix and asymptotic variance for GI/M/1-type Markov chains

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Frontiers of Mathematics in China 2014年第4期9卷 863-880页

作者： Yuanyuan LIU pengfei wang Yanmin XIE School of Mathematics New Campus Central South University Changsha 410083 China

We investigate deviation matrix for discrete-time GI/M/1-type Markov chains in terms of the matrix-analytic method, and revisit the link between deviation matrix and the asymptotic variance. Parallel results are obtained for continuous-time GI/M/1-type Markov chains based on the technique of uniformization. We conclude with A. B. Clarke＇s tandem queue as an illustrative example, and compute the asymptotic variance for the queue length for this model.

关键词： GI/M/1-type Markov chains deviation matrix asymptoticvariance matrix-analytic method

Repeated Compton scattering in a strong magnetic field

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Science China(Physics,Mechanics & Astronomy) 2012年第10期55卷 1931-1937页

作者： wang pengfei CHOU ChihKang HAN JinLin National Astronomical Observatories Chinese Academy of SciencesBeijing 100012China

Repeated scatterings of unpolarized photons by non-relativistic electrons in a static and uniform magnetic field are investigated by using the Boltzmann equation with quantum mechanical correction factors for the stimulated scattering *** resulting Kompaneets equation depends explicitly on the electron cyclotron frequency and the incidence angle of the incoming photons relative to the direction of the magnetic *** evolutionary behavior of the photon spectrum and energy density is highly anisotropic with respect to the static external magnetic *** applications of our results to the X-ray emission from compact and massive stellar objects are discussed in detail and those to the interaction of the microwave background radiation with the hot electrons in galactic clusters are discussed briefly.

关键词： electromagnetic waves: magnetospheric propagation X-ray scattering: interactions with matter neutron stars

Matrix approach to verification and enforcement of nonblockingness for modular discrete-event systems

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Science China(Information Sciences) 2020年第11期63卷 324-326页

作者： Xiaoguang HAN pengfei wang Zengqiang CHEN College of Electronic Information and Automation Tianjin University of Science and Technology College of Artificial Intelligence Nankai University Tianjin Key Laboratory of Intelligent Robotics Nankai University

Dear editor,Discrete-event systems (DESs) constitute an important class of dynamical systems with discretestates and event-driven dynamics (see [1]). In practice, a DES, also called a plant, may be composed of several... 详细信息

关键词： Discrete event systems Nonblockingness verification and enforcement Semi-tensor product of matrices Finite state automata